early tail feathers = roo?? 10 day old PICS

Here are some pics of my 10 day old hatch. They are supposed to be a mix of pure breed austraulop and white orpington, some pure , some mixed. I definately got 2 austrolorps there, one mixed half half, and maybe one white orp.

I was wondering if those 2 chicks with early tail feathers and wing feathers mean its a roo?? They are only 10 days old and those tail feather came in 2-3 days ago, when they were a week old. The other 2 still have puff ball tails.
Either way I will be happy with a 50/50 mix.

I'm not sure how it's worked out for others, but it seems that most of the ones that I've had that got their tail feathers first ended up being female. It works for me with about 90% of the time. At hatch, some breeds have longer wing pin feathers, which indicate females, but I'm not sure what all breeds this is reliable for.

In general, boys feather in slower than the girls in many breeds like Orpingtons. The first to get tails are usually the girls. If you have some who are almost bare on the back, losing fuzz faster than the feathers come in, those are probably the boys.